APPLICATION AND OPERATION INFORMATION (cont.)
UC1835/6 Foldback Current Limiting
UC1835 UC1836
UC2835 UC2836
UC3835 UC3836
UC3835/36 TYPICAL APPLICATIONS
Low Current Application
using the UC3836 internal drive transistor
Typical Output Current vs V
IN
and V
OUT
of the UC3836 internal drive transistor
for P
DISS
= 0.5W (approx.)
High Current Application
using drive transistor Q
2
to increase Q
1
base drive
and reduce UC3836 power dissipation
Parallel Pass Transistors
can be added for high current or
high power dissipation applications
EQUATIONS:
R
1
= 0.100 V/I
OUT
(MAX)
R
2
= (V
OUT
- 2.5V/1mA)
R
3
= ((V
IN
- V
BE
- V
SAT
)*BETA(min))/I
OUT
(max)
UNITRODE INTEGRATED CIRCUITS
7 CONTINENTAL BLVD.
•
MERRIMACK, NH 03054
TEL. (603) 424-2410
•
FAX 603-424-3460
4
TI [ TEXAS INSTRUMENTS ]
